In January 1528, the Ottomans under Gazi Husrev-beg took command of Jajce, Banja Luka and Ključ, followed by Krbava and Lika in the spring of that year.
In 1102 Croatia joined personal union with Hungary and the Hungarians formed new territorial units called Župas; Modruš became the seat of one of these Župas and soon became the seat of the Krbava-Modruš episcopacy.
It stretches in the direction north–south, and it extends from the mountain pass that separates it from Mala Kapela, along the Krbava field to the west and the Una River canyon to the east, and ending near Gračac where it touches on Velebit.